Rear Suspension Q's
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Joined: Aug 2000
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From: Camano Island, WA
Rear Suspension Q's
Some thoughts on lowering the back end:
It appears that the leaf springs are what keep the axle from sliding sideways out from under the truck (pardon the obvious, but this is my first leaf sprung vehicle). That means there is considerable force applied to the spring-to-frame mounting points. Now, for the sake of argument, let's say the OEM shackle is 4". To lower the back 2", the shackle has to be 4" longer than that, or double the original length. Seems to me that this will apply twice as much force at the top and bottom of the shackle as more leverage applied by the increased length. It looks like all this will cause the axle to slide sideways away from the truck on a hard corner (more than it does now), changing the forward angle of the rear tires, and also possibly causing other undesirable problems: more frame twist as the limit of the bushing is reached, the hanger could be bent or torn off, unexpected handling characteristics on hard cornering, etc..
I guess what I'm getting at is, are these potential side effects worth it to gain a slightly lower center of gravity and appearance improvement? Is this why the Roush package uses a different spring curve rather than a longer shackle?
Are there any suspension experts on board that could confirm all this or tell me I'm full of crap? Anybody with drop shackles ever seen any hanger or spring eyelet damage?
This all came about when I was deciding lower the back a bit and got to wondering about the stresses involved and whether I could trust my welding skills.
Mark
'00 Silver L
p.s. I didn't even look at the FAQ, so there. :P
It appears that the leaf springs are what keep the axle from sliding sideways out from under the truck (pardon the obvious, but this is my first leaf sprung vehicle). That means there is considerable force applied to the spring-to-frame mounting points. Now, for the sake of argument, let's say the OEM shackle is 4". To lower the back 2", the shackle has to be 4" longer than that, or double the original length. Seems to me that this will apply twice as much force at the top and bottom of the shackle as more leverage applied by the increased length. It looks like all this will cause the axle to slide sideways away from the truck on a hard corner (more than it does now), changing the forward angle of the rear tires, and also possibly causing other undesirable problems: more frame twist as the limit of the bushing is reached, the hanger could be bent or torn off, unexpected handling characteristics on hard cornering, etc..
I guess what I'm getting at is, are these potential side effects worth it to gain a slightly lower center of gravity and appearance improvement? Is this why the Roush package uses a different spring curve rather than a longer shackle?
Are there any suspension experts on board that could confirm all this or tell me I'm full of crap? Anybody with drop shackles ever seen any hanger or spring eyelet damage?
This all came about when I was deciding lower the back a bit and got to wondering about the stresses involved and whether I could trust my welding skills.
Mark
'00 Silver L
p.s. I didn't even look at the FAQ, so there. :P